Hanski C, Hanski M L, Zimmer T, Ogorek D, Devine P, Riecken E O
Klinikum Benjamin Franklin der Freien Universität Berlin, Department of Gastroenterology, Germany.
Cancer Res. 1995 Feb 15;55(4):928-33.
The expression of the mucin-bound sialyl-Lewisx epitope is increased in the tissue of most colorectal carcinomas and in the sera of about 30% of tumor patients. In colon cancer, a portion of the sialyl-Lex groups detectable with the monoclonal antibody AM-3 is located on MUC1 (C. Hanski et al., Cancer Res., 53: 4082-4088, 1993). In order to characterize the major colon carcinoma-associated sialyl-Lex-positive glycoprotein components, the tissue- and serum-derived antigens were investigated. The buoyant densities of the sialyl-Lewisx-positive antigens from tumor and normal colonic tissues and from sera of patients with colon carcinoma and healthy donors correspond to that of mucins (1.40 g/ml). The sialyl-Lex-positive mucins purified from both tissues elute under nonreducing conditions in the void volume of a Sepharose CL-2B column, indicating a molecular mass more than 2 x 10(7) daltons. They yield in immunoblot after SDS gel electrophoresis under reducing conditions a main band at an apparent M(r) 880,000. Radioactive labeling revealed that the band at M(r) 880,000 is the major protein component in sialyl-Lewisx-positive mucins both from tumor and normal colonic tissue. In sera of colon carcinoma patients, the sialyl-Lex moiety is also detectable mainly on a M(r) 880,000 glycoprotein band and, additionally, on a M(r) 140,000 molecule as well as on alpha 1-acid glycoprotein. Sera from healthy donors exhibited only a sialyl-Lex-positive glycoprotein with the apparent M(r) 140,000. Sandwich ELISA as well as immunoblots of mucins purified from the colon carcinoma cell line LS174T indicated that the sialyl-Lex moiety migrating in the M(r) 880,000 band is located on MUC2 protein core. Together, these data suggest that sialyl-Lex antigen in colon, colon carcinoma, and the sera of patients with this tumor is located on the MUC2 molecule, consisting of several subunits with an apparent M(r) 880,000, linked via disulfide bridges. The increase of sialyl-Lex expression in colon carcinomas appears to be mainly due to a more frequent transfer of sialyl-Lex moieties onto the mucin core in tumor tissue.
大多数结直肠癌组织以及约30%的肿瘤患者血清中，黏蛋白结合的唾液酸化路易斯x表位的表达增加。在结肠癌中，用单克隆抗体AM - 3可检测到的部分唾液酸化路易斯x基团位于MUC1上（C. Hanski等人，《癌症研究》，53: 4082 - 4088，1993）。为了鉴定主要的结肠癌相关唾液酸化路易斯x阳性糖蛋白成分，对组织和血清来源的抗原进行了研究。肿瘤和正常结肠组织以及结肠癌患者和健康供体血清中唾液酸化路易斯x阳性抗原的浮力密度与黏蛋白的浮力密度一致（1.40 g/ml）。从两种组织中纯化的唾液酸化路易斯x阳性黏蛋白在非还原条件下于琼脂糖CL - 2B柱的空体积中洗脱，表明其分子量超过2×10⁷道尔顿。在还原条件下进行SDS凝胶电泳后，它们在免疫印迹中产生一条表观分子量为880,000的主要条带。放射性标记显示，分子量为880,000的条带是肿瘤和正常结肠组织中唾液酸化路易斯x阳性黏蛋白的主要蛋白质成分。在结肠癌患者血清中，唾液酸化路易斯x部分也主要在分子量为880,000的糖蛋白条带上可检测到，此外，在分子量为140,000的分子以及α1 - 酸性糖蛋白上也可检测到。健康供体的血清仅显示出一种表观分子量为140,000的唾液酸化路易斯x阳性糖蛋白。夹心ELISA以及从结肠癌细胞系LS174T纯化的黏蛋白的免疫印迹表明，在分子量为880,000条带中迁移的唾液酸化路易斯x部分位于MUC2蛋白核心上。总之，这些数据表明，结肠、结肠癌以及该肿瘤患者血清中的唾液酸化路易斯x抗原位于MUC2分子上，该分子由几个表观分子量为880,000的亚基组成，通过二硫键连接。结肠癌中唾液酸化路易斯x表达的增加似乎主要是由于唾液酸化路易斯x部分更频繁地转移到肿瘤组织中的黏蛋白核心上。
